MERCEDES, Texas (Border Report) — The largest international dam on the Texas/Mexico border has acquired unsafe sinkholes in need of costly repairs for decades, the U.S. International Boundary and Water Commission head told Border Report.
Limestone sinkholes have been found in the Amistad International Dam, which will require repairs done on the Mexican side, U.S. IBWC Commissioner Maria-Elena Giner said Tuesday night during an IBWC field meeting with stakeholders in the small border town of Mercedes.
Giner, whose office is in El Paso, said millions of U.S. funds will be needed to complete reconstruction on the six-mile-long international dam, and all needed repairs are on the Mexican side.
“Amistad has been declared by the Corps of Engineers as potentially unsafe. That’s Level II, there’s a Level I which is even a higher level of urgency. So, right now we’re working with Mexico on the repairs. And these repairs are going to be potentially hundreds of millions of dollars,” Giner told Border Report.
Back in 2007, a joint report of the IBWC found the dam “potentially unsafe, and that the entire dam foundation is in need of further evaluation and study.”
The report, signed by technical advisors from the United States and Mexico, said then that “urgent actions are needed.”
Another inspection in 2017 also found it to be potentially unsafe because of the large sinkholes that apparently have existed since the dam was built in the 1960s.
Giner told stakeholders — including ranchers and farmers who were gathered Tuesday evening for information on how much water to expect from the Rio Grande amidst a prolonged drought — that issues at Amistad Dam are long overdue and need to be addressed.
Mexico has pledged $20 million for Phase I of the project, and Giner said 56% of the costs are due by the United States. However, she did not say how much that would be.
“Right now we have sufficient funds to get us started but as we start advancing the development we’ll get a better feel for what the true cost of the project is,” Giner told Border Report.
The head engineer for the U.S. section of the IBWC says they have been working with Mexico on this project for several years.
“Limestone under the dam that’s one of the reasons we’re having these sinkholes. So, we have been working with Mexico for several years now and we’re at the tail end now of having a solution for that and proceeding with a design and construction project,” Isela Canava, principal U.S. engineer for IBWC, said.
Amistad Dam and reservoir at twilight on Feb. 21, 2023 in Del Rio, Texas. Lake Amistad, the international reservoir bordering Texas and Mexico which provides water to the Rio Grande, is strained by severe drought conditions. (Brandon Bell/Getty Images File Photo)
The international dam and reservoir are owned and managed by both countries and located about 12 miles north of Del Rio in Val Verde County, Texas, on the border with Coahuilla, Mexico. The dam regulates water flow of the Rio Grande downstream to the Rio Grande Valley.
The dam is 254-feet tall and 6 miles long but most — 4.25 miles — are in Mexico. Only 1.82 miles of the dam are on the U.S. side.
The reservoir can store 3.2 million acre feet of water and is vital to ensuring water levels in the Rio Grande, especially for farmers in the Rio Grande Valley.
An ongoing drought has kept water levels low at Amistad.
(Texas Water Development Board Graphic)
As of Wednesday, the Amistad Reservoir was only 26.8% full, according to the Texas Water Development Board. Data shows water levels have consistently dropped since the start of 2023 and currently at their lowest levels in the past year. Last December, the reservoir was 46.8% full.
Several growers told IBWC staff Tuesday that every drop of water needs to be preserved. Several said that watermelon, citrus and onion crops in the Rio Grande Valley of deep South Texas are suffering and reduced because there isn’t enough water for farming.
Sandra Sanchez can be reached at SSanchez@BorderReport.com.
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